Apparatus for producing oil from subsurface deposits



R. A. AUCOIN Sept. 3, 1940.

APPARATUS FOR PRODUCING OIL FROM SUBSURFACE DEPOSITS Filed Nov. 19, 1937 Q .s G

INVENTOR.

ATTORNEY.

Patented Sept. 3, 1940 UNITED STATES APPARATUS FOR PRODUCING OIL FROM SUBSURFACE DEPOSITS Riley A. Aucoin, Overton, Tex., assignor to Standard Oil Development Company, a corporation of Delaware Application November 19, 1937, .Sel'ial No. 175,356

3Claims.

The present invention is directed to an apparatus for producing oil from oil wells.

In the art of producing oil from oil wells it has become common practice to aid the movement of 8 the oil from the formation to the surface, when the pressure in the formation is not sufficiently great to maintain a constant flow of oil to the surface, by injecting gas into the oil at various points along the conduit connecting the forma- 10 tion to the surface. Another expedient which has been adopted is the borehole pump. The latter is expensive and involves operating. difliculties'. The former loses its usefulness when the formation pressures drops below a certain level.

According to the present invention, both the gas lift principle and the pump principle are employed. In the apparatus of the present invention-a chamber is arranged in the borehole, a head of oil is permitted to build up in the chamber by virtue of the formation pressure until the head becomes sufliciently great to open a valve against the pressure of a supply of high pressure gas introduced into the well. At this time the connection between the chamber and 88 the formation is broken and the high pressure gas forces the oil out of the chamber to the surface until the head of oil in the chamber is reduced below a certain predetermined value when the supply of high pressure gas is shut off so and the chamber is *again fluidly connected to the formation. Means are provided for preventing the high pressure gas from acting on the formation. The nature of the present invention will be 35 better understood from the accompanying drawing in .which Figure 1 is a vertical section through a well containing the arrangement of the present invention;

Fig. 2 is a detail view, partly in section, of a 40 modified form of the arrangement of the present invention; and

Fig. 3 is a detail view of an element shown in Fig. 2; and I I .Fig. 4 is a longitudinal section of one type of valve which may be employed in connection with thearrangement of the present invention but the specific? of the preserif; invention.

Referring'to the di awing in detail, I designates 50 the earth having'ian oil. bearing sand 2, connected to the surface by borehole 3. Arranged in the borehole is a. casing. having a closed upper end provided with a pressure gauge 5 and a gas inlet controlled by a valve 1. Projecting through the 55 top of'the casing is a pipe 8 terminating near the surface.

pstruction of which forms no part the lower end of the casing in an enlarged chamber 9 having a constricted lower open end in which is arranged a seat for a check valve, such as a ball valve iii. ,A tube II is suspended in chamber 9 from pipe 8 to which it is joined 5 by a weld I2 or a suitable bushing. Mounted outside the pipe 8 and above or below chamber 9 is a packer i3 adapted to seal off .the upper portion of the casing from the formation.

Outside the casing pipe 8 is provided with suit-- 10 able valves and with a pressure gauge l4.

Arranged on pipe 8 below the junction of pipe 8 and tube II is a valve H of the gas lift type which works on one side against gas in the upper part of the casing and on the other side against I oil in the chamber 9. This valve can be one of the manyavailable types of conventional gas lift valves operatedby a pressure differential. Its specific construction forms no part of the present invention. A valve capable of operating on any desired differential, which will be dictated by the formation pressure, will be selected. For example, the conditions of the well may make it advisable to employ a valve operating on a diflerential of about 100# per sq. in. in conjunction with g5 a gas supply at 300# per sq.in. In this case the valve will open to admit gas into chamber 9 when the head of oil in the chamber amounts to 200# per sq. in. As soon as the valve opens the pressure in chamber 9 'will increase due to the inrush 3 In operation oil flows into chamber 9 and thence into pipe 8 until the head of oil above valve I5 is sufficient to cause it to open and admit high pressure gas into chamber 9. Thiscauses the oil to flow downwardly in chamber 9, thereby closing the ball valve l0 and sealing off 0 the formation. The high pressure gas forces the oil contained in the pipe and in chamber 9 to Assoon as the head of oil above valve I5 is reduced to a predetermined value valve I 5 will close,"ball valve ill will open and g the cycle will be repeated. V

As previously stated and as is apparent, the packer l3 can be above .or below the chamber 9. This packer prevents the high'p'ressure gas from acting on,the formation and thereby decreasing the flow of oil from thejormation.

While chamber 9 may in some cases beomitted, it is a very important part of the combination. Chamber 9 makes it possible for a larger amount of oil to accumulate for a given head. This is important because it increases the ratio .of the volume of oil to the volime of gas admitted through valve l5 and thereby minimizes the possibility of the occurrence of slippage of thegas past the oil. Without chamber 9 such slippage may occur and greatly reduce the efliciency of the combination.

The arrangement shown is extremely useful in regulating the flow of oil from producing wells. By adjusting the distance between the chamber 9 and the oil sand, the time required to build up a sufllcient head of oil above valve [5 to open it can be regulated, thereby regulating the rate of production. This feature is a very marked advantage since it reduces the amount of attention that must ordinarily be given the producing well.

In Fig. 2 an arrangement is shown in which the gas inlet valve is arranged inside the chamber 9 instead of on pipe 8. Arranged in pipe 8 above chamber 9 is a plug l6 having a radial passage I! which opens at the center of the lower face of the plug into the chamber 9. Arranged around the face of plug l6 are a plurality of longitudinal passages l6 for conducting oil from chamber 9 to pipe 8. Suspended in chamber 9 from passage I1 is pipe H. Attached to pipe H by a screwthread connection is a gas lift valve l9 shown in detail in Fig. 4.

Referring to Fig. 4, the essential elements .of the gas lift valve are a gas inlet 20, a gas chamber 2|, a gas outlet 22 and a main plunger 23 having a cone shaped end 24 adapted to be seated on one end of gas outlet 22. Plunger 23 is carried by a sleeve 25 and is normally held in open position by a spring 26. The end of sleeve 25 near the head of the plunger is provided with ports 21 for permitting the passage of gas from chamber 2| to the outlet 22 which in turn is connect'ed to chamber 9 by port 35.

At the other end of sleeve 25 a second plunger 28, of smaller diameter than the inside of the sleeve, is slidingly mounted. It is adapted to be seated on a valve seat 29 at the end of an annular opening 30 which is in free communication with the-exterior of the valve, that is, theoil chamber 9 through passage 36. Plunger 28 is V normally held off of this seat by a spring 3i. It

is also adapted to seat at the end of a chamber 32 which is connected to gas chamber 2| by a series of ports 33. Chamber 32 is also connected by a by-pass 34 to the chamber in which the rear end of plunger 23 rides.

In Fig. 4 the parts of the valve are shown in the position they assume before the valve is associated with the combination shown and when the valve is in use under a sufficient oil head to set it into operation. With the parts in the position shown the valve is connected in place as shown in Fig. 2. As soon as the upper end of the casing is filled with high pressure gas this gas enters the valve through inlet 20 and fills chamber 2|, entering chamber 32 through ports 33. The pressure of the gas on plunger 28 forces it off its seat at the end of chamber 32 against the force of spring 3| to its seat 29. This permits the high pressure gas to flow through bypass 34 to the rear of plunger 23 which is thereby forced onto its seat at the end of gas outlet 22.. against the force of spring 26.

When oil enters chamber 9 it flows through the opening 36 at the lower end of the valve to the rear of plunger 28. When the head of oil in chamber 9 becomes sufiiciently great it forces plunger 28 off its seat 29 to its seat at the end of chamber 32, thereby cutting of! the gas supply to by-pass 34. The high pressure gas already contained behind plunger 23 is forced out by the action of spring 26 through by-pass 34 and through the annular space 30 and passage 36 into chamber 9. Simultaneously valve 24 is unseated from the end of chamber 22 permittinghigh pressure gas to flow through outlet 22 into chamber 9 through port 35. The parts remain in this position until the head of oil is dissipated whereupon the gas pressure again forces plunger 28 to its seat 29 and the cycle of operations begins again.

It is apparent that many changes may be made in the arrangement illustrated and described above without departing from the scope of the present invention. It may be mentioned, here that the utilization of a plurality of gas lift valves along pipe 8 in the conventional'manner is contemplated in the practice of the present invention.

The nature and objects of the present invention having been thus -described and illustrated what is claimed as new and useful and is desired to be secured by Letters Patent is:

1. An arrangement for producing oil from a subsurface formation through a borehole connecting the formation to the surface comprising a casing in the borehole, a packer in said casing intermediate its ends sealing off the upper portion of the casing from the formation, a pipe in the borehole extending from the surface to below the packer and arranged for fluid connection with the formation, an enlarged portion in said pipe forming a chamber, a tube of reduced cross sectional area arranged in said pipe and extendin from above the chamber into the chamber and terminating adjacent the bottom thereof, the upper end of said tube having its outer surface connected to the inner surface of the pipe in a fluid tight manner and opening into said pipe, a check valve at the lower end of said chamber, a conduit at the upper end of said chamber connecting said chamber to the casing above said packer, means for supplying high pressure gas to the casing above said packer and a valve arranged in said conduit adapted to be normally held in closed position by said .high pressure gas to prevent flow of gas to said chamber, and to be opened upon the attainment of a predete minedhead of liquid in said pipe.

2. An arrangement for producing oil from a subsurface formation through a borehole connecting the formation to the surface comprising a casing in said bor he, a packer in said casing intermediate i J ends for sealing off the upper end of the ca .ing from said formation, means for applying big 1 pressure gas to the upper end of said casing, a pipe arranged in said casing from the surface to a point below said packer, an enlarged portion in said pipe forming a chamber, a plug in said pipe above said chamber having a radial passage having one of its ends opening into the casing above the packer and the other of its ends terminating in such chamber, a tube connected to said latter end and depending into said chamber, a valve arranged in said tube for establishing fluid connection betweenthe casing and the chamber, said valve being of a type which is adapted to be normally held in closed position by said high pressure gas to prevent flow of said gas to said chamber, and to be opened upon the attainment of a predetermined head of liquid in said pipe, a check valve at the lower end of said chamber and longitudinal passages in said plug for establishing a fluid connection between said chamber and said pipe.

3. An arrangement for producing oil from a subsurface formation through a boreholeconnecting the formation to the surface comprising a casing in the borehole, a packer in said casin intermediate its ends sealing of the upper por-" tion 01' the casing from the formation, a pipe in the borehole extending from the surface to below the packer and arranged for fluid connection with the formation, an enlarged portion in said pipe forming a chamber, a conduit for establishing fluid connection between said pipe and one end of said chamber, a conduit connecting the other end of said chamber with the upper portion of said casing above said packer, means for supplying high pressure gas to the portion of the casing above thepacker, a valve arranged in said last mentioned conduit adapted to be normally held in closed position by said high pressure gas to prevent flow of said gas to said chamber and to be opened upon the attainment of a predetermined head of liquid in said pipe and a check valve at the lower end of said chamber.

- RILEY A. AUCOIN. 

